This invention relates generally to gas turbine engine, and more particularly, to methods for replacing nuggeted combustor liner panels used with gas turbine engines.
A turbine engine includes a compressor for compressing air which is mixed with a fuel and channeled to a combustor wherein the mixture is ignited within a combustion chamber for generating hot combustion gases. At least some known combustors include a dome assembly, a bolt banding, and liners to channel the combustion gases to a turbine, which extracts energy from the combustion gases for powering the compressor, as well as producing useful work to propel an aircraft in flight or to power a load, such as an electrical generator. The liners are coupled to the dome assembly with the bolt banding, and extend downstream from the bolt banding to define the combustion chamber.
At least some known liners include a plurality of panels that are connected together with riveted, bolted, or welded connections. A portion of the panels include cooling nuggets formed between adjacent panels, that extend radially outwardly from the panels and away from the combustion chamber. Accordingly, such cooling nuggets are not subjected to the same degree of heat as portions of the panels adjacent the combustion chamber, and as such, during operation thermal stresses may be induced within the panels. Over time, continued operation with thermal stresses may cause panels to thermally fatigue, causing weakening and/or cracking to develop within the panels.
Current repair methods include welding thermal fatigue cracks. Additionally, patches may be attached to areas of panels that are weakened by thermal stresses. However, if the thermal stresses have induced thermal fatigue or distress in larger areas of the panels or in a plurality of panels, the combustor may not have enough structural integrity within such panels to enable patches to be attached. In such cases, repair of such panels is not a feasible option, and instead the entire combustor liner is replaced. Because the liner is coupled to the bolt band and the dome assembly, often the entire combustor must be disassembled for the liner to be replaced. Furthermore, when the fasteners are removed from the bolt band and dome assembly, precise dimensional relations between the components may be altered and as a result, special tooling may be required during re-assembly. Thus, replacing a combustor liner including cooling nuggets may be a time-consuming and expensive process.
In an exemplary embodiment, a method facilitates replacing a portion of a nuggeted combustor liner within a gas turbine engine combustor in a cost-effective and reliable manner. The combustor includes a combustion zone that is defined by an inner and an outer liner. The inner and outer liners each include a series of panels and a plurality of nuggets formed by adjacent panels. A plurality of the panels include cooling nuggets. The method includes the steps of cutting through at least one panel nugget to remove at least one panel from the combustor, and installing at least one replacement panel into the combustor such that the series of panels are arranged in steps relative to one another.
In another aspect of the invention, a method is used to replace at least one deteriorated combustor liner panel within a gas turbine engine combustor that includes an annular liner including a multinugget region, a mulithole region, an inner surface, and a plurality of nuggets. The method includes the steps of cutting through at least one nugget downstream from the at least one deteriorated combustor liner panel to be replaced and within at least one of the liner multinugget region and the liner multihole region, removing the at least one deteriorated combustor liner panel from the combustor, and welding at least one replacement panel to at least one existing panel within the combustor for each deteriorated combustor liner panel removed.